Scullcap
StarScutellaria lateriflora
Synonyms: Cassida lateriflora, Scutellaria lateriflora f. albiflora, Scutellaria polybotrya, Scutellaria lateriflora var. albiflora, Scutellaria lateriflora var. axillaris, Scutellaria lateriflora f. rhodantha
Western Herbalism Properties
Traditional Uses
Cherokee herbalists prepared infusions and decoctions of the root for gynecological purposes, including the regulation of menstruation, expulsion of the afterbirth and the treatment of breast pains, and used a root compound as a kidney medicine and for diarrhea (Hamel and Chiltoskey, 1975; Taylor, 1940). The Iroquois took an infusion of the powdered roots to keep the throat clean and as a prophylactic against smallpox (Herrick, 1977). In nineteenth- and early twentieth-century Eclectic and Physiomedical practice the aerial herb was widely employed as a nervine, antispasmodic and mild sedative for hysteria, nervous excitability, restlessness, insomnia and the convulsions of teething or hydrophobia (King and Felter, 1898).
Gallery
Botanical Description
Scutellaria lateriflora, the Virginia or blue skullcap, is a herbaceous perennial of the mint family (Lamiaceae) native to moist woodlands, swamp margins, meadows and stream banks across much of North America from Quebec and British Columbia south to Florida and California. From a slender creeping rhizome the plant produces erect, slender, square, branching stems 30 to 80 centimetres tall, glabrous or sparsely pubescent, often somewhat reddish at the nodes. The opposite, petiolate leaves are thin, ovate to lance-ovate, 3 to 8 centimetres long, with coarsely serrate margins, an acuminate apex and a rounded to truncate base. Small two-lipped tubular flowers about 6 to 8 millimetres long, pale blue to lavender-blue with a white throat, are borne in slender one-sided racemes from the axils of the upper leaves, the calyx bearing the characteristic scutellate dorsal protuberance that gives the genus its name. The fruit consists of four small wrinkled nutlets enclosed in the enlarged persistent calyx. The plant lacks the strong aroma of many mints.
Active Constituents
Baicalin
Flavone glycosideConcentration: Major flavonoid of the aerial parts
The principal flavonoid glycoside; baicalin and its aglycone bind the benzodiazepine site of GABA-A receptors, providing a plausible mechanism for the herb's traditional anxiolytic and sedative use, alongside antioxidant activity.
Baicalein
Flavone (aglycone)Concentration: Aerial parts
The aglycone of baicalin with documented affinity for GABA-A benzodiazepine binding sites and for the 5-HT7 serotonin receptor; contributes anxiolytic and anti-inflammatory activity in experimental models.
Wogonin and wogonoside
Flavone / flavone glycosideConcentration: Aerial parts
Methoxylated flavones that also interact with GABA-A receptors and show anti-inflammatory and neuroprotective activity in laboratory studies.
Scutellarin / scutellarein
Flavone glycoside / aglyconeConcentration: Aerial parts
Characteristic Scutellaria flavones with antioxidant and vasoprotective properties; scutellarin is among the constituents reported to bind the 5-HT7 receptor.
Dihydrobaicalin and ikonnikoside I
Flavonoid glycosideConcentration: Aerial parts (minor)
Minor flavonoid constituents identified as 5-HT7 receptor ligands, potentially contributing to the mood-modulating profile of the whole extract.
Apigenin, luteolin and hispidulin
FlavoneConcentration: Minor flavones
Additional flavones with reported GABAergic and anti-inflammatory activity that add to the overall calming action attributed to skullcap.
⚠ Drug Interactions
CNS depressants and sedatives (benzodiazepines, alcohol, sedating antihistamines)
Skullcap flavonoids act at the benzodiazepine site of GABA-A receptors, so concurrent use with other sedatives could produce additive central nervous system depression and drowsiness.
Clinical note: Use caution when combining with sedatives, anxiolytics, hypnotics or alcohol; watch for excess drowsiness.
Drugs metabolised by CYP3A4 / CYP1A2 / CYP2D6
Scutellaria lateriflora extract has inhibited several cytochrome P450 enzymes (including CYP3A4) in vitro, which could raise plasma levels of drugs that depend on these enzymes for clearance.
Clinical note: Theoretical only; relevance in humans is unconfirmed. Consider caution with narrow-therapeutic-index drugs metabolised by CYP3A4.
Preparation Methods
Infusion (herbal tea) of the aerial parts
Parts: aerial parts, leaves, flowering tops
Steep about 1-2 g of dried aerial parts in 150 mL hot water for 10-15 minutes; taken 1-3 times daily, often in the evening, as a mild relaxant for nervous tension and to support sleep. Use only correctly identified, authenticated material.
Tincture
Parts: aerial parts
An ethanolic tincture of the fresh or dried aerial parts is used in small doses as a nervine. Rare reports of liver injury attributed to skullcap products have been linked to adulteration with hepatotoxic Teucrium (germander) species rather than to genuine Scutellaria lateriflora; source from suppliers who verify botanical identity.
Clinical Studies
American Skullcap (Scutellaria lateriflora): A Randomised, Double-Blind Placebo-Controlled Crossover Study of its Effects on Mood in Healthy Volunteers
Forty-three healthy volunteers took 350 mg S. lateriflora three times daily or placebo for two weeks each. Total Mood Disturbance on the Profile of Mood States fell significantly with skullcap but not placebo; the Beck Anxiety Inventory change was not significant in this relatively non-anxious group, suggesting a mood-enhancing effect without loss of energy.
Efficacy and Tolerability of a Chemically Characterized Scutellaria lateriflora L. Extract-Based Food Supplement for Sleep Management: A Single-Center, Controlled, Randomized, Crossover, Double-Blind Clinical Trial
Sixty-six adults with mild-to-moderate primary insomnia took a characterized S. lateriflora extract (400 mg/day) or placebo for 56 days with a washout crossover. The supplement improved Pittsburgh Sleep Quality Index and related sleep-wake measures versus placebo and was well tolerated.
Historical Texts
Native American ethnobotany (Cherokee and other nations)
Pre-19th century, orally transmittedEclectic and physiomedical writings; King's American Dispensatory
19th centuryReferences
- Brock C, Whitehouse J, Tewfik I, Towell T. American Skullcap (Scutellaria lateriflora): A Randomised, Double-Blind Placebo-Controlled Crossover Study of its Effects on Mood in Healthy Volunteers . Phytotherapy Research (2014) [DOI]
- Lin RC, Chan CO, et al. (LiverTox). Skullcap. LiverTox: Clinical and Research Information on Drug-Induced Liver Injury . National Institute of Diabetes and Digestive and Kidney Diseases (NIH Bookshelf, NBK548757) (2020) [DOI]
This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.
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